A short nap is typically 10 to 20 minutes long. This duration keeps you in the lighter stages of sleep, giving you a quick boost in alertness, memory, and mood without causing post-sleep grogginess (sleep inertia).
A two-hour sleep generally functions more as a mini-sleep session than a traditional nap.
Researchers say a 20 minute nap is the best length. A short nap like this allows your mind and body to rest without entering the deeper stages of sleep.
Yes, daytime naps can help lower cortisol levels. By providing a quick reset, they reverse some of the physical stress caused by daily demands or a poor night's sleep.
The "30/90 rule" is a sleep guideline recommending you either nap for less than 30 minutes or take a full 90-minute snooze. This helps you dodge sleep inertia—that heavy, disoriented feeling caused by waking up mid-way through deep sleep.
Back in 2016, one retired Navy SEAL told an interviewer that whenever he felt he needed a midday pick-me-up, he took an 8–minute power nap in an interesting position. His afternoon snooze left him feeling rejuvenated—almost like he'd slept through a whole night.
Einstein's daytime naps were incredibly short, often lasting only a few seconds to a couple of minutes. He favored a brief "micro-nap" to tap into a highly creative, half-asleep mental state, which he then paired with a massive 10 hours of sleep per night.
When cortisol (the primary stress hormone) remains elevated for too long, it impacts your metabolism, blood pressure, and immune system. Here are 10 common warning signs of chronically high cortisol levels:
Waking up at 3 a.m. with a racing heart is typically triggered by a combination of blood sugar drops, a hyperactive nervous system, and natural circadian fluctuations. You can stop these awakenings by stabilizing your body and resetting your natural rhythm.
Napping provides an active, physical reboot for your brain and body. By briefly pausing cognitive load, a short nap reduces sleepiness, boosts mental clarity, clears out proteins that cause fatigue, lowers stress hormones, and triggers memory consolidation.
Inemuri (居眠り) is the Japanese practice of sleeping briefly in social or work environments. Unlike the Western siesta, which is often viewed negatively, inemuri in Japan is seen as a sign of dedication to work. An 18-minute micro-nap seems ideal for improving performance and alertness.
Leonardo da Vinci is famously associated with an extreme polyphasic sleep cycle known as the Uberman cycle. According to historical lore, he bypassed a traditional night's sleep to take 15 to 20-minute naps every four hours, totaling just 1.5 to 2 hours of rest a day.
Napping also can lead to issues such as: Feeling groggy right after waking. This is known as sleep inertia. That groggy feeling could make it harder to work and feel alert right after a nap.
Yes. During his playing career, Kobe Bryant famously survived on just 3 to 4 hours of sleep a night, often practicing a "biphasic" sleep schedule. He typically broke this up into two 2-hour blocks, waking up as early as 4:00 a.m. to begin his legendary workouts.
Yes, a 2-hour nap is significantly better than no sleep. While you may wake up feeling temporarily groggy, getting some sleep helps clear sleep pressure (adenosine) from the brain, restores energy, improves cognitive performance, and can even lower stress hormones like cortisol.
Naps, in contrast to caffeine, have been shown to enhance not only alertness and attention, but also some forms of memory consolidation. In particular, naps (daytime sleep between 5–90minutes) appear to improve performance on non-medio-temporal lobe dependent, procedural skills (Mednick et al.
Cortisol, a stress hormone that primes the body for action, alertness and energy, does the opposite starting to rise at 3am to 5am and building towards its morning peak.
A cortisol spike feels like a sudden jolt to your "fight-or-flight" system. You will likely experience a racing heart, tense muscles, jitteriness, and a surge of anxious, restless energy. It often manifests as sudden, racing thoughts or a feeling of being on edge.
Waking up at 3 a.m. and struggling to fall back asleep is often linked to a deficiency in Vitamin D or Vitamin B12, as well as the mineral magnesium.
Research links high cortisol levels to Vitamin D and Vitamin C deficiencies. Additionally, a lack of Vitamin B12 is associated with an exaggerated stress response and elevated cortisol during chronic stress.
The most scientifically backed, natural cortisol reducer is Ashwagandha, an adaptogenic herb. Clinical studies show it can significantly reduce cortisol levels (by up to 25% or more) and help the body manage stress.
High cortisol (hypercortisolism) creates a persistent "fight-or-flight" state. It typically feels like a mix of intense physical stress and emotional exhaustion. Symptoms include severe anxiety, insomnia or waking up abruptly at night, brain fog, abdominal weight gain, muscle weakness, and easy bruising.
But, while experts say that an adult should get between 7–9 hours of rest every night (Sleep Council), some of the world's most successful people don't follow that advice, spending much less time asleep than is recommended.
Albert Einstein did not believe in a personal God who intervenes in human affairs or answers prayers. Instead, he subscribed to "Spinoza's God"—a pantheistic view equating God with the harmony, rationality, and physical laws of the universe. He viewed himself as a "religious nonbeliever".
As scholar Roger Ekirch uncovered through historical study of literature, art and diaries, people would once head to bed when it got dark, sleep for four hours, wake for a while, and then slide into a “second sleep” for another four hours.